In the related art, there is known an inkjet recording apparatus that forms an image on a recording medium by ejecting liquid droplets of an ink from a plurality of nozzles provided in an inkjet head.
In the inkjet recording apparatus, the nozzles may be clogged due to air bubbles generated in the inkjet head, foreign matters which are mixed into the inkjet head, and the like, and thus a problem such as ejection failure may occur in some cases. In addition, in accordance with the kind of the ink, when being left without use for a long period of time, an ink viscosity in the vicinity of the nozzles may increase due to descending of ink particles and the like, and thus it may be difficult to obtain stable ink ejection performance.
Therefore, there is known an inkjet recording apparatus in which a circulation flow passage of ink is provided in a head chip of the inkjet head to allow air bubbles and the like inside the head to flow through the circulation flow passage in combination with the ink.
For example, Patent Literature 1 discloses an inkjet head including nozzles which are arranged in a plurality of rows, a common supply flow passage (a fluid inlet passage) through which ink is commonly supplied to each of respective pressure chambers (pump chambers) each communicating to each nozzle, and a common circulation flow passage (recirculation channel) with which a plurality of circulation flow passage, from which ink in the vicinity of the nozzle is discharged, communicate.